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Saturday, December 13, 2025

December 13, 2025

BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA SATURDAY, DECEMBER 13, 2025 ALL TIMES ARE…

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BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

SATURDAY, DECEMBER 13, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0705E
SUNSET:  1612E

INCREASING CLOUDS AND A STEADY SOUTHWESTERLY TODAY….

This morning featured a beautiful orange and red sky right
before sunrise. We had a peak of sun before overcoming to
mostly overcast conditions. During the late morning we had
a couple appearances from the sun, but for the majority of
the day we have been in the clouds.

Temperatures have slightly recovered with the passing of the
arctic front, but we still remain below normal. The overnight
low was 23F and so far we have warmed to 34F. Dew points have
remained rather stable, hovering in the upper teens.

Winds were out of the west-southwest this morning and shifted to
a more southwesterly flow by mid morning. So far, the average
wind speed is around 11mph. The peak gust so far of 28mph occurred
at 11:16am this morning.

Visibility started around 50 miles this morning and then rapidly
improved to 80 miles. Around 1pm we were back to around 50 miles.

The maximum temperature so far today is 34F degrees, which is
7 degrees below the normal high of 41F. The minimum temperature
since midnight is 23F degrees, which is 3 degrees below the
normal low of 26F.

————————————————————–

Today’s Observations:

7 A.M.
Weather: Thinly scattered cirrus, few stratocumulus NE-S
Temperature: 23F; Dew Point: 18F; Relative Humidity: 80%
Wind: WSW @ 8 kts
Sea-level pressure: 1020.0 mb; 30.12 in. Hg: falling, then
rising
Visibility: 50 miles
6-hr Max temp: 27F
6-hr Min temp: 23F
24-hr Precip: 0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 250 -SCT 50 200/23/18/2408/012/ FEW SC NE-S/
8/501 53008 10027 20023

10 A.M.
Weather: Overcast cirrostratus, few stratocumulus NE-S
Temperature: 28F; Dew Point: 18F; Relative Humidity: 64%
Wind: SSW @ 8 kts
Sea-level pressure: 1019.5 mb; 30.11 in. Hg: falling, then
more rapidly
Visibility: 80 miles
3-hr Precip: 0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 220 OVC 80 195/28/18/2008/011/ FEW BINOVC S
FEW SC NE-S/ 8/506 58005

1 P.M.
Weather: Overcast altocumulus, few stratocumulus distant
ENE-SSE
Temperature: 34F; Dew Point: 19F; Relative Humidity: 54%
Wind: WSW @ 12 kts
Sea-level pressure: 1017.7 mb; 30.05 in. Hg: falling, then
more slowly
Visibility: 50 miles
6-hr Max temp: 34F
6-hr Min temp: 23F
6-hr Precip: 0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 80 OVC 50 177/34/19/2412/005/ FEW SC DSNT ENE-SSE/
8/55/ 56018 10034 20023

————————————————————–

SUMMARY FOR FRIDAY, DECEMBER 12, 2025

TEMPERATURE (DEGREES F)
MAX…….33   NORMAL…..41
MIN…….18   NORMAL…..26
MEAN……26   NORMAL…..34

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-8
TOTAL DEPARTURE FOR THE MONTH………………………-82 [-7.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….39  DEPARTURE……..+8
TOTAL HEATING UNITS FOR THE MONTH……………439  DEPARTURE…….+81
TOTAL HEATING UNITS FOR THE SEASON………….1556  DEPARTURE……..-6
TOTAL HEATING UNITS LAST SEASON TO DATE……..1309  DEPARTURE……+247

PEAK WIND GUST (MPH):
Note: Instruments designated #1 = Main Tower, #2 = South Tower,
F420C, Contacting, Merlin, and Richards are all on Main Tower.
E=Estimated *=Last of multiple occurrences

F420C (Official)………..41 W    @   12:20 P.M.
VECTOR #1 (1-Sec)……….41 W    @   12:20 P.M.
VECTOR #2 (1-Sec)……….43 W    @   12:28 P.M.
DAVIS #1……………….41 W    @   12:27 P.M.
DAVIS #2 ………………42 W    @   12:19 P.M.
RMY #1 (Instantaneous)…..42 WNW  @   03:39 P.M.
RMY #2 (Instantaneous)…..45 W    @   12:19 P.M.
MERLIN…………………39 W
RICHARDS (C5C) (Inst)……42 W    @   12:20 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………28 W    @   12:32 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..29 W    @   01:17 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..31 WNW  @   12:32 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………31 W    @   01:17 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………31 W    @   01:18 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..27 W    @   01:17 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..30 WNW  @   12:33 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………23 WNW  @   01:39 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..17.6 W [423 total miles] VECTOR #1………………17.0
VECTOR #2………………17.7
DAVIS #1……………….18.1 W
DAVIS #2……………….17.6 WNW
RMY #1…………………16.0 W
RMY #2…………………17.2 W
RICHARDS (C5C)………….16.8

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.18
TOTAL PRECIPITATION FOR THE MONTH…………..0.95 DEPARTURE…..-1.20
TOTAL PRECIPITATION FOR THE YEAR (2025)…….45.41 DEPARTURE…..-5.21

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE…..-0.4
TOTAL SNOWFALL FOR THE MONTH………………..0.6 DEPARTURE…..-3.1
TOTAL SNOWFALL FOR THE SEASON (2025-2026)…….0.7 DEPARTURE…..-5.5

————————————————————–

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN)/SUN(%)/PEAK GUST/VEC1/RMY GUST
PEAK GUST: F420C (Official)
VEC1: Vector #1 1-second gust
RMY:  R.M. Young #1 wind gust recording system (Instantaneous)
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

12/1   42/27/35/-2/T/0.0/547/98          37 WNW VEC1 37 WNW RMY 38
12/2   36/27/32/-5/0.85/T/000/00         38 N   VEC1 38 NNE RMY 38
12/3   37/27/32/-4/0.06/0.6/423/76       28 NW  VEC1 29 NNW RMY 30
12/4   38/15/27/-9/T/T/255/46            60 NW  VEC1 59 WNW RMY 61
12/5   25/8/17/-19/T/T/510/92            30 NW  VEC1 30 NW  RMY 30
12/6   39/25/32/-3/T/T/122/22            21 W   VEC1 21 W   RMY 22
12/7   39/27/33/-2/0.00/0.0/248/45       24 W   VEC1 24 W   RMY 24
12/8   31/12/22/-13/T/T/…/..           43 NW  VEC1 43 NW  RMY 44
12/9   28/9/19/-15/0.00/0.0/…/..       33 SSW VEC1 33 SSW RMY 33
12/10  46/28/37/+3/0.04/T/…/..         50 SSW VEC1 50 SSW RMY 51
12/11  37/21/29/-5/0.00/0.0/…/..       51 WNW VEC1 51 WNW RMY 53
12/12  33/18/26/-8/0.00/0.0/…/..       41 W   VEC1 41 W   RMY 42

12/13  The low since midnight is 23F, the daily normal low is 26F.

————————————————————–

DECEMBER DAILY RECORDS TO DATE

NONE.

————————————————————–

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)

RECORDS FOR DECEMBER 13
HIGH 60 IN 1984
LOW 0 IN 1893
PRECIP 1.45 INS. IN 1983
SNOWFALL 9.2 INS. IN 2007
PEAK GUST 81e WNW IN 1976

RECORDS FOR DECEMBER 14
HIGH 62 IN 1901
LOW -6 IN 1893
PRECIP 1.94 INS. IN 2002
SNOWFALL 8.0 INS. IN 1907
PEAK GUST 78e ENE IN 1941

TODAY’S REPORT PREPARED BY: Amanda Joly

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Blue Hill Observatory & Science Center · Legal

Data Use & Privacy Policy

Please read the full Policy before accessing Observatory data · Effective January 1, 2025

Notice: By accessing, downloading, or using any Blue Hill Observatory data or services, you unconditionally accept and agree to be bound by this Policy in its entirety. If you do not agree, you may not access or use Observatory data.
Effective January 1, 2025 · Milton, Massachusetts · bluehill.org
Part I — Data Use Policy
§ 01

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